Receivers out of tubing and bolts out of round stock. I need to make and weld 2 nuts on it to hold a top picatinny rail. The tube is 6-4 IIRC. ..060". I'll get the actual specs later if it's that important.

You can TIG weld Titanium. Use a DC negative torch and keep the part under argon until the part cools below 500degrees F. You can also use a glovebox with argon flooded in it if the part is really critical.

Is this for a 50 cal? I have a customer that makes titanium recievers for 50 caliber machine guns for the US gov. Cool stuff.

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A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.

You can TIG weld Titanium. Use a DC negative torch and keep the part under argon until the part cools below 500degrees F. You can also use a glovebox with argon flooded in it if the part is really critical.

Is this for a 50 cal? I have a customer that makes titanium recievers for 50 caliber machine guns for the US gov. Cool stuff.

Anything that can oxidize can explosively combust given the right particle size and air/fuel ratio.

A titanium pressure vessel went up in a fab shop on a plant near us, it had not been cleaned 100% so a minor "bang" when they cut it, took out the gas and air lines, it now fed the fire, the titanium ignited properly, there was not much left of that shop, well basically a hole in the ground.

I live off-grid and have several projects for which I'd like to be able to weld. I will be teaching myself from videos this winter out in BFE. Realistically if I want to weld on electric I need a bigger genset or a generator welder. I know one can use series'd batteries but that seems to be an emergency get-you-home deal rather than a way to build a full project.

I might want to weld aluminum, but have no current projects with it. I often have some aluminum scrap and I love working with the stuff, so I presume I'd weld on it if I could but its not currently needed.

If I could weld cast iron, I would have various neighbors wanting their stoves repaired... again I'd like the ability but it is not really needed.

I do currently need to weld a light-weight roll cage, I want to make a custom 50cc hack (no reg/insurance) to run my shepherd around the mesa's nasty dirt backroads, and I also hope to build a few biomass gasifiers. I expect these projects would call for welding on between 18ga sheet steel up through maybe 1/4" steel plate or angle iron.

I also expect to do jewelry work this winter which could be O/A, or butane or air/propane instead if I don't need to deal with O/A tanks otherwise. The largest torch I might use for such work would be a Meca Midget or similar.

I currently have no really good way of cutting serious steel, I can cut everything I need to but its very slow with a hacksaw or my deWalt (don't bother) 18v angle grinder. I would certainly like a torch setup for cutting.

So, I am thinking that even though most people think of O/A welding as old-skool that it might be the best choice for me. Probably with a smaller torch system like the Midget.

But dealing with the tanks seems a pain. I read that I should NEVER transport acetylene in an enclosed vehicle? Is a welding shop likely to stop me from doing so? I have no way of using a hitch mount, the best I could do is put it on the hood or modify the vehicle (for which I'd need the torch in the first place). I live past the end of BFE down dirt roads, I think the nearest air-gas retailer is about 2 hours away, the dirt roads are only a couple miles but it is a half hour to town IF I find someone who runs tanks back and forth between Taos and Santa Fe.

I have a shed I can store the tanks upright in. I might want to bring tanks into the main cabin's greenhouse during use but wouldn't store them there. I'd probably prefer smaller tanks so they're easier to move but have no idea what size would be good for me.

So.... can I maybe get away with hauling the acetylene home from a random autobody shop in town that might swap my cylinders for me on their ride? From Santa Fe (no one else in vehicle)? How dangerous (or illegal) is it? I know many people here have hauled gasoline in water bladders.... I would, but I like to understand my risks.

Is dealing with the gas cylinders worth the bother, or should I get a better genset and electric welder (tig? mig? I CAN haul argon co2 etc in a suv right?)

Is there anything else less explosive than acetylene which will still make a good cone of inert gas as its combustion byproduct for welding (I understand that oxy/propane is poor for welding due to this reason)?

Also, how important is regulator quality for light tubing and sheet work? Money is very tight and two stage regulators bloody expensive, do I need them? If I'm just using it occasionally could cheapo china regulators make sense? Used name brand ones?

Thanks for any advice here.

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government is an illusion in the minds of governors

I've transported acetylene bottles on their side in my pickup truck bed. It's not illegal or dangerous. However, the bottle can't be used immediately after being on it's side. The bottle must sit upright for ~ 1 hour so the acetone can drip back through the sintered metal and leave a gas pocket for the acetylene.

Also, the size of the bottle determines the rate at which acetylene can be removed - it's a fraction of the bottle size. The ratio of acetylene to oxygen is 2:5 or ~ 1:3 , but the oxygen bottle does not have a flow limit like acetylene so the size of the acetylene bottle will determine the maximum welding thickness. For 1/4" steel, one of the larger personally owned cylinders should be big enough the last time I checked.

Do you have propane at home? It sounds like you might want to look into oxy-propane for cutting and brazing. You could do a lot of what you're talking about by fillet brazing, and propane would work fine for that, easier to transport/store and cheaper. The torch tips should be made for propane or modified from the acetylene tips.
I thought the rule of thumb was to keep an acetylene bottle upright for twice as long as it had been on it's side before using it.